Heh. Have you ever seen a software system that has been fixed, patched, enhanced, updated, upgraded, and modified over a period of thirty years? It has a name in the industry. Its called "spaghetti code". Hmmm. Sounds exactly like what you just described.
Can I completely rule out the possibility of an incompetent designer? I guess not. I would just rather not believe in such a thing.
But of course the system after 30 years hasn't really been "designed", now has it? It has instead been hacked, kludged, and munged. (Nicely descriptive words, aren't they?) Its amazing how much old software systems resemble nature.
Software and DNA are both information.